package com.zq.mycloud.gateway.util;

import org.springframework.http.HttpHeaders;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.Optional;

/**
 * @author ：zhang qiang
 * @package :com.zq.mycloud.gateway.util
 * @date ：Created in 2020/12/11 下午5:11
 * @description：获取用户ip
 * @modified By：
 * @version: $
 */

public class IpUtil {
    private static final String IP_UNKNOWN = "unknown";
    private static final String IP_LOCAL = "127.0.0.1,0:0:0:0:0:0:0:1";
    private static final int IP_LEN = 15;

    /**
     * 获取用户真实ip
     * @param headers
     * @param remoteAddress
     * @return 返回真实ip
     */
    public static String getIP(HttpHeaders headers, InetSocketAddress remoteAddress) {
        String ipAddress = headers.getFirst("x-forwarded-for");
        if (ipAddress == null || ipAddress.length() == 0 || IP_UNKNOWN.equalsIgnoreCase(ipAddress)) {
            ipAddress = headers.getFirst("Proxy-Client-IP");
        }
        if (ipAddress == null || ipAddress.length() == 0 || IP_UNKNOWN.equalsIgnoreCase(ipAddress)) {
            ipAddress = headers.getFirst("WL-Proxy-Client-IP");
        }
        if (ipAddress == null || ipAddress.length() == 0 || IP_UNKNOWN.equalsIgnoreCase(ipAddress)) {
            ipAddress = Optional.ofNullable(remoteAddress)
                    .map(address -> address.getAddress().getHostAddress())
                    .orElse("");
            if (IP_LOCAL.contains(ipAddress)) {
                try {
                    InetAddress inet = InetAddress.getLocalHost();
                    ipAddress = inet.getHostAddress();
                } catch (UnknownHostException e) {
                    // ignore
                }
            }
        }

        // 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
        if (ipAddress != null && ipAddress.length() > IP_LEN) {
            int index = ipAddress.indexOf(",");
            if (index > 0) {
                ipAddress = ipAddress.substring(0, index);
            }
        }
        return ipAddress;
    }

}

